Improvement in sewing-machines



D. HARRIS.

Sewing Machine.

Patented Jan. 19. 1858.

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v UNITED STATES PATENT O FICE.

DANIEL HARRIS, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN SEWING-MACHINES.

Specification forming part of Letters Patent No. 19,14], dated January19, 1858.

To aJZ whom it may concern Be it known that I, DANIEL HARRIS, of Boston,in the county of Suffolk and State of Massachusetts, have invented anImprovement'in Producing Tension or Friction upon the Thread in aSewing-Machine, the nature and operation of which I hereby declare to befully set forth in the following specification, reference beinghad tothe accompanying drawings, to which this specification and lettersrefer.

The invention consists in an improved manner of regulating the deliveryof the thread from the spool or other source to the needle byatension-clamp located at any convenient intermediate point.

Figure 1 of the drawings represents a side elevation of thetension-clamp as applied upon goose-neck, where I generally prefer toplace it. Fig. 2 is a vertical section of the clamp, and Fig. 3ahorizontal section. of it.

A in the drawings denotes a screw pin or spindle applied on top of thegooseneck, or located in any other convenient place.

B is a piece of rubber or gum-elastic tubing placed on the spindle andresting upon a plate or base, 0, or directly upon the goose-neck orplate to which the spindle may be applied, Upon the top of this tubing awasher, D, made large enough in diameter to cover or nearly cover thetubing B, is placed, as seen in Figs. 1 and 2. This washer I generallyprefer, for wear, to make of parchment, as this is tough and yielding,while it is smooth and somewhat oily, and permits the thread to runeasily when pressed against it. It may, however, be made of any smooth,dry, and somewhat yielding material that will keep properly in place,wear well, and prevent the rubber from touching the thread. Over thisdisk, and through an aperture, a, in the spindle, the threadF passes, aparchment disk, G, covered by a rubber or gum-elastic tube, H, beingplaced over the thread, as seen in Fig. 2. On top of the spindle a screwcap or nut, I, is fixed, the requisite pressure being produced upon thethread by rotation of this nut, said pressurebeing upon the length ofthread between the disks.

In sewing with thread fed directly to the needle from a common spool thethread is delivered too fast, being all taken from the spool at eachstitch,when, in order tomake the stitching tight, it should be partiallytaken from the slack of the previous loops or stitches. To remedy thisthe thread is generally rewound from the common spool onto a largebobbin, r

' use. In sewing the chain-stitch much depends upon the tightness withwhich the stitches are drawn into the cloth, as when the sewing is looseit easily unravels. Unless the looper 0r beak has a strong spring thrownforward in taking each loop, so as to take up the slack of the precedingloop, the tension must be continually varied in order to produce theproper draw upon this next preceding loop or stitch. This spring-throwis very apt to break the thread. WVhen the stitches are very long, allor nearly all of the thread taken-from the spool by the stitch but asthe stitch is shortened so much needle in its descent is required toform the thread is not needed,while the needle in its de-' scent takesthe same length from the spool. This leaves the stitch loose, and toovercome this the needle at its next descent shoves down part of itsthread from this previous slack, and

to make it do so such variablepressure must be applied to the threadback of the needle in the different stitches as to cause the needle totake its thread from previous slack, instead of from the spool, until.the stitch is properly drawn in, when it will take the rest from thespool. To do this without producing a j erk upon the thread suffioientto break it, as is often the case where the looper has a spring-' throwgiven to it, the thread for this purpose is passed between the tworubber springs or tubes, contact with the rubber to unduly bind thethread being prevented by the intervention of the smooth and yieldingdisks, the pressure being varied according to the stitch by thescrew-cap.

I claim- The specific device herein described for applying tension tothe thread during its pasdegree of intensity required, .substantially assage from the bobbin or spool to the needle set forth. that is, causingit to run through the eye of Intestimony whereof I have hereto set mythe spindle and between two disks of parehsignature this 26th day'ofJune, A. D. 1857.

ment when said disks are placed upon the DANL. HARRIS.

spindle betweentwo india-rubber tubes or cyllVitnesses: J

inders, which are liable to be compressed in N. A. DYER,

the direction of the axis of the spindle to any FRANCIS GOULD. v

